|Cole crops like broccoli, cauliflower, and cabbage can be direct seeded into your garden around July 21, assuming the ground can be worked, but it's better to start them indoors around June 23 and then transplant them into the garden around August 12. Do the same with lettuce and spinach.
Plant onion starts and potatoes around July 3. Sow the seeds of peas (sugar snap and english) at the same time. If the ground is still frozen, then plant these as soon as the ground thaws.
Do you want to grow tomatoes, peppers, and eggplants? Start these indoors around June 23. Then, around August 28 you should start watching the weather forecast and, as soon as no frost is forecast, go ahead and transplant those into the ground.
Now, for all the summer vegetables like beans, cowpeas, corn, squashes, pumpkins, cucumbers, watermelons, gourds and sunflowers, you should plant those seeds directly into the ground around September 1, or if your soil is still very cold, once the soil is near 60° F in temperature. Having said that, we note that your location has a shorter than average growing season. Many summer vegetables need more days to mature than your area will provide. For that reason, we recommend you get a head-start by starting these summer vegetables indoors around August 12, and transplant those seedlings out after the danger of frost is past.